Non-Utilisation Of Plot - Charges/Fines

Dear all, I am in negotiation for buying a plot in Sector B. It's a 10 Marla plot. My main purpose of this plot is to keep it for my kids and they can use in years to come. But

I am abroad and have tried bahria help-desk, but they haven't been very helpful. Can someone please shed light on following

1. Charges/fee for non-utilization of plot

2.And maintenance fee every month

Thanks in advance